Fingerprint sensing apparatus, fingerprint readout circuit, and touch display panel

ABSTRACT

A fingerprint sensing apparatus includes a plurality of fingerprint sensors and a fingerprint readout circuit. The fingerprint sensors may be configured to operate in a fingerprint sensing cycle. The fingerprint readout circuit may be coupled to the plurality of fingerprint sensors via a plurality of sensing lines. The fingerprint readout circuit may be configured to control the fingerprint sensors to operate in the fingerprint sensing cycle. The fingerprint sensing cycle includes an initialization period, an exposure period and a readout period. A voltage of a reset node in each fingerprint sensor among the fingerprint sensors is reset to a first voltage in a reset period before the fingerprint sensing cycle starts. The voltage of the reset node in each fingerprint sensor is initialized to an initial voltage in the initialization period. The initial voltage is different from the first voltage.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of U.S. provisional patentapplication Ser. No. 63/116,169, filed on Nov. 20, 2020. The entirety ofthe above-mentioned patent application is hereby incorporated byreference and made a part of this specification.

BACKGROUND Technical Field

The disclosure relates to fingerprint sensing; particularly, thedisclosure relates to a fingerprint sensing apparatus, a fingerprintreadout circuit, and a touch display panel.

Description of Related Art

Fingerprint recognition is a commonly used technology for securityprotection. In order to reduce the size reduction of electronic productsand increase convenience, an optical fingerprint sensor array is oftenintegrated in a touch display panel. However, due to the in-displayfingerprint sensor structure, the quality of the captured fingerprintimage data may be unstable, which increases the false rejection rate(FRR) and/or the false acceptance rate (FAR) of fingerprint recognition.

SUMMARY

The disclosure is direct to a fingerprint sensing apparatus, afingerprint readout circuit, and a touch display panel, especially to afingerprint sensing apparatus, a fingerprint readout circuit, and atouch display panel embedded with in-display fingerprint sensorstructure, so as to improve the stability of fingerprint image quality.

In the disclosure, the fingerprint sensing apparatus includes aplurality of fingerprint sensors and a fingerprint readout circuit. Thefingerprint sensors may be configured to operate in a fingerprintsensing cycle. The fingerprint readout circuit may be coupled to theplurality of fingerprint sensors via a plurality of sensing lines. Thefingerprint readout circuit may be configured to control the fingerprintsensors to operate in the fingerprint sensing cycle. The fingerprintsensing cycle includes an initialization period, an exposure period anda readout period. A voltage of a reset node in each fingerprint sensoramong the fingerprint sensors is reset to a first voltage in a resetperiod before the fingerprint sensing cycle starts. The voltage of thereset node in each fingerprint sensor is initialized to an initialvoltage in the initialization period. The initial voltage is differentfrom the first voltage.

In the disclosure, the fingerprint readout circuit, configurable to becoupled to a touch display panel. The touch display panel may include aplurality of fingerprint sensors arranged in a sensor array and a gateon array circuit. The fingerprint readout circuit may be coupled to theplurality of fingerprint sensors via a plurality of sensing lines. Thefingerprint readout circuit may be coupled to the gate on array circuit.The fingerprint readout circuit may be configured to output at least onestart pulse signal and at least one clock signal to control the gate onarray circuit to output reset signals and selecting signals. The resetsignals and the selecting signals may be configured to control at leastone fingerprint sensing zone of the fingerprint sensors arranged in thesensor array to operate in a fingerprint sensing cycle. The fingerprintsensing cycle may include an initialization period, an exposure period,and a readout period. According to the reset signals, a voltage of areset node in each fingerprint sensor among the fingerprint sensors maybe reset to a first voltage in a reset period before the fingerprintsensing cycle starts. The voltage of the reset node in each fingerprintsensor may be initialized to an initial voltage in the initializationperiod. The initial voltage is different from the first voltage.

In the disclosure, the touch display panel may include a plurality ofsensing lines, a plurality of fingerprint sensors. The plurality offingerprint sensors may be configured to operate in a fingerprintsensing cycle. The plurality of fingerprint sensors may be coupled to afingerprint readout circuit via the sensing lines. The fingerprintsensing cycle includes an initialization period, an exposure period anda readout period. A voltage of a reset node in each fingerprint sensoramong the fingerprint sensors may be reset to a first voltage in a resetperiod before the fingerprint sensing cycle starts. The voltage of thereset node in each fingerprint sensor may be initialized to an initialvoltage in the initialization period. The initial voltage is differentfrom the first voltage.

Based on the above, according to the fingerprint sensing apparatus, thefingerprint readout circuit, and the touch display panel of thedisclosure, the reset period is arranged before the fingerprint sensingcycle to reset the voltage of the reset node of the fingerprint sensors.As a result, the fingerprint image quality becomes more stable.Therefore, the false rejection rate (FRR) and/or the false acceptancerate (FAR) of fingerprint recognition is reduced and the accuracy of thefingerprint recognition is improved.

To make the aforementioned more comprehensible, several embodimentsaccompanied with drawings are described in detail as follows.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the disclosure, and are incorporated in and constitutea part of this specification. The drawings illustrate exemplaryembodiments of the disclosure and, together with the description, serveto explain the principles of the disclosure.

FIG. 1 is a schematic diagram of a fingerprint sensing apparatusaccording to one embodiment of the disclosure.

FIG. 2 is a schematic diagram of a fingerprint sensor according to oneembodiment of the disclosure.

FIG. 3 is a schematic timing chart of a fingerprint sensor according toone embodiment of the disclosure.

FIG. 4 is a schematic timing chart of a fingerprint sensor according toone embodiment of the disclosure.

FIG. 5 is a schematic diagram of a fingerprint sensor array according toone embodiment of the disclosure.

FIG. 6 is a schematic timing chart of a fingerprint sensor arrayaccording to one embodiment of the disclosure.

FIG. 7 is a schematic timing chart of a fingerprint sensor arrayaccording to one embodiment of the disclosure.

FIG. 8 is a schematic diagram of a touch display panel including afingerprint sensor array according to one embodiment of the disclosure.

FIG. 9 is a schematic timing chart of a touch display panel including afingerprint sensor array according to first embodiment of thedisclosure.

FIG. 10 is a schematic timing chart of a touch display panel including afingerprint sensor array according to second embodiment of thedisclosure.

FIG. 11 is a schematic timing chart of a touch display panel including afingerprint sensor array according to third embodiment of thedisclosure.

FIG. 12 is a schematic timing chart of a touch display panel including afingerprint sensor array according to fourth embodiment of thedisclosure.

FIG. 13 is a schematic timing chart of a touch display panel including afingerprint sensor array according to fifth embodiment of thedisclosure.

FIG. 14 is a schematic timing chart of a touch display panel including afingerprint sensor array according to sixth embodiment of thedisclosure.

FIG. 15 is a schematic diagram of a fingerprint readout circuitaccording to one embodiment of the disclosure.

FIG. 16 is a schematic diagram of a touch display panel according to oneembodiment of the disclosure.

DESCRIPTION OF EMBODIMENTS

Reference will now be made in detail to the exemplary embodiments of thedisclosure, examples of which are illustrated in the accompanyingdrawings. Whenever possible, the same reference numbers are used in thedrawings and the description to refer to the same or like components.

Certain terms are used throughout the specification and appended claimsof the disclosure to refer to specific components. Those skilled in theart should understand that electronic device manufacturers may refer tothe same components by different names. This article does not intend todistinguish those components with the same function but different names.In the following description and rights request, the words such as“comprise” and “include” are open-ended terms, and should be explainedas “including but not limited to . . . ”.

The term “coupling (or connection)” used throughout the wholespecification of the present application (including the appended claims)may refer to any direct or indirect connection means. For example, ifthe text describes that a first device is coupled (or connected) to asecond device, it should be interpreted that the first device may bedirectly connected to the second device, or the first device may beindirectly connected through other devices or certain connection meansto be connected to the second device. The terms “first”, “second”, andsimilar terms mentioned throughout the whole specification of thepresent application (including the appended claims) are merely used toname discrete elements or to differentiate among different embodimentsor ranges. Therefore, the terms should not be regarded as limiting anupper limit or a lower limit of the quantity of the elements and shouldnot be used to limit the arrangement sequence of elements. In addition,wherever possible, elements/components/steps using the same referencenumerals in the drawings and the embodiments represent the same orsimilar parts. Reference may be mutually made to related descriptions ofelements/components/steps using the same reference numerals or using thesame terms in different embodiments.

It should be noted that in the following embodiments, the technicalfeatures of several different embodiments may be replaced, recombined,and mixed without departing from the spirit of the disclosure tocomplete other embodiments. As long as the features of each embodimentdo not violate the spirit of the disclosure or conflict with each other,they may be mixed and used together arbitrarily.

FIG. 1 is a schematic diagram of a fingerprint sensing apparatusaccording to one embodiment of the disclosure. Referring to FIG. 1 , afingerprint sensing apparatus 100 may include a plurality of fingerprintsensors 110 and a fingerprint readout circuit 120. The fingerprintsensors 110 may be configured to operate in a fingerprint sensing cycle.The fingerprint readout circuit 120 may be coupled to the plurality offingerprint sensors 110 via a plurality of sensing lines 130. Thefingerprint readout circuit 120 may be configured to control thefingerprint sensors 110 to operate in the fingerprint sensing cycle. Thefingerprint sensing cycle includes an initialization period, an exposureperiod and a readout period. A voltage VP of a reset node P in eachfingerprint sensor among the fingerprint sensors 110 is reset to a firstvoltage in a reset period before the fingerprint sensing cycle starts.The voltage VP of the reset node P in each fingerprint sensor 110 isinitialized to an initial voltage in the initialization period. Theinitial voltage is different from the first voltage.

In one embodiment, the reset node P is a node electrically coupled to aphoto sensor of the fingerprint sensor 110. The voltage VP of the resetnode P is reset to the first voltage before the fingerprint sensingcycle, and as a result, the fingerprint image quality becomes morestable, and thereby reduces the false rejection rate (FRR) and/or thefalse acceptance rate (FAR) of fingerprint recognition.

FIG. 2 is a schematic diagram of a fingerprint sensor according to oneembodiment of the disclosure. Referring to FIG. 1 and FIG. 2 , afingerprint sensor 200 in FIG. 2 may be one embodiment of thefingerprint sensor 110 in FIG. 1 , but the disclosure is not limitedthereto. The fingerprint sensor 200 may include a photo sensor S1, afirst capacitor C1, a reset switch M1, a source follower M2 (as atransistor), and a select switch M3. The photo sensor S1 may beconfigured to sense light in the exposure period. The photo sensor S1may include a first terminal and a second terminal. The first capacitorC1 may include a first terminal and a second terminal. The firstterminal of the photo sensor S1 and the first terminal of the firstcapacitor C1 may be electrically coupled to the reset node P. The secondterminal of the photo sensor S1 and the second terminal of the firstcapacitor C1 may be electrically coupled to a bias node to receive abias voltage Vbias. The reset switch M1 may include a first terminal, asecond terminal, and a control terminal. The source follower M2 mayinclude a first terminal, a second terminal, and a control terminal. Theselect switch M3 may include a first terminal, a second terminal, and acontrol terminal. The first terminal of the reset switch M1 and a gate(i.e. the control terminal) of the source follower M2 may beelectrically coupled to the reset node P. The second terminal of thereset switch M1 and the first terminal of the source follower M2 may beelectrically coupled to a power supply node to receive a voltage signalVsig. The second terminal of source follower M2 may be electricallycoupled to the first terminal of the select switch M3. The secondterminal of the select switch M3 may be configured to provide a sensingvoltage as an output signal at the output terminal Output. When thesource follower M2 is turned on, the voltage on the first terminal ofthe select switch M3 follows the voltage of the reset node P.

In one embodiment, when the reset switch M1 is turned on, the reset nodeP is electrically coupled to the power supply node supplied with thevoltage signal Vsig. The voltage signal Vsig is kept at the firstvoltage in the reset period. The voltage signal Vsig is kept at theinitial voltage in the initialization period. In one embodiment, thefirst voltage may be 0V, and the initial voltage may be a work voltageVDD, but the disclosure is not limited thereto. In this manner, duringthe reset period, the voltage VP of the reset node P is reset to thefirst voltage, and during the initialization period, the voltage VP ofthe reset node P is initialized to the initial voltage. The voltage VPof the reset node P is reset to the first voltage before the fingerprintsensing cycle, and as a result, the fingerprint image quality becomesmore stable when performing multiple fingerprint sensing cycles, andthereby reduces the false rejection rate (FRR) and/or the falseacceptance rate (FAR) of fingerprint recognition.

In one embodiment, the fingerprint readout circuit 120 is configured tooutput the voltage signal Vsig to a touch display panel. That is to say,the fingerprint sensor may be integrated into the touch display panel.Therefore, the degree of integration of the fingerprint sensingapparatus and the touch display panel is improved.

FIG. 3 is a schematic timing chart of a fingerprint sensor according toone embodiment of the disclosure. Referring to FIG. 1 to FIG. 3 , in thetiming chart 300, a voltage signal to control a gate (i.e., the controlterminal) of the reset switch M1 is represented by VM1. A voltage signalto control a gate (i.e., the control terminal) of select switch M3 isrepresented by VM3. The voltage VP of the reset node P is represented byVP. The initialization period of the fingerprint sensing cycle isrepresented by P_INIT. The exposure period of the fingerprint sensingcycle is represented by P_EXP. The readout period of the fingerprintsensing cycle is represented by P_READ.

In one embodiment, the fingerprint readout circuit 120 may read out asensing voltage of each fingerprint sensor 110 via the correspondingsensing line 130 in the readout period. The sensing voltage follows thevoltage VP of the reset node P. The fingerprint readout circuit 120 maygenerate a sensing result of each fingerprint sensor 110 based on avoltage variation between the initial voltage and the sensing voltage.

Specifically, the initialization period P_INIT of a fingerprint sensingcycle is from time t301 to time t302. The exposure period P_EXP of thefingerprint sensing cycle is from time t302 to time t304. The readoutperiod P_READ of the fingerprint sensing cycle is from t304 to timet305. As depicted in FIG. 3 , the exposure period P_EXP of thefingerprint sensing cycle is regarded from the falling edge of thevoltage signal VM1 to the falling edge of the voltage signal VM3; and inanother aspect, the exposure period P_EXP of the fingerprint sensingcycle may be regarded from the rising edge of the voltage signal VM1 tothe rising edge of the voltage signal VM3. More precisely, regarding toeach fingerprint sensor 110, the initialization operation and thereadout operation depicted in FIG. 3 happens right away when theswitches turned on or off. The initialization period P_INIT of anotherfingerprint sensing cycle is from time t305 to time t306. At time t301,the voltage signal VM1 is configured to be switched from a low level toa high level to turn on the reset switch M1. After the M1 is turned on,the reset node P is electrically coupled to the power supply node toreceive the voltage signal Vsig, and the voltage VP is graduallyincrease towards the voltage signal Vsig by charging the first capacitorC1 during the initialization period P_INIT. In one embodiment, thevoltage signal Vsig is kept at the initial voltage in the initializationperiod P_INIT and the initial voltage may be a work voltage VDD, but thedisclosure is not limited thereto. At time t302, the voltage signal VM1is configured to be switched from the high level to the low level toturn off the reset switch M1. The voltage VP is initialized to theinitial voltage (work voltage VDD) and the photo sensor S1 is configuredto sense light in the exposure period P_EXP. During the exposure periodP_EXP, the voltage VP is gradually reduced. At time t303, the voltagesignal VM3 is configured to be switched from a low level to a high levelto turn on the select switch M3. After the select switch M3 is turnedon, a sensing voltage follows the voltage VP of the reset node P. Thatis to say, the voltage VP is provided to the output terminal Output as asensing voltage. Output terminals Output of a column of fingerprintsensors 110 are coupled to a sensing line 130. The fingerprint readoutcircuit 120 reads out the sensing voltage of the fingerprint sensor 110(in a column) via the sensing line 130. At time t304, the fingerprintreadout circuit 120 generates a sensing result of the fingerprint sensor110 based on a voltage variation A V between the initial voltage (workvoltage VDD) and the sensing voltage. In other words, the voltagevariation A V is the voltage difference between the initial voltage(which the voltage VP of the reset node P may achieve during theinitialization period when M1 is turned on) and the voltage VP of thereset node P when M3 is turned off. In this manner, the fingerprintsensing apparatus 100 may realize the function of fingerprintrecognition based on the sensing result.

FIG. 4 is a schematic timing chart of a fingerprint sensor according toone embodiment of the disclosure. Referring to FIG. 1 to FIG. 4 ,ideally, during the initialization period P_INIT, the voltage VP of thereset node P is charged from 0V to work voltage VDD since the resetswitch is turned on for initialization of the fingerprint recognition.In one embodiment, a residual voltage VR may exist due to the residualcharge in the first capacitor C1, and the stability of the readoutfingerprint images is therefore decreased, thereby might increase thefalse rejection rate (FRR) and/or the false acceptance rate (FAR) offingerprint recognition. In order to enhance the stability of thefingerprint images and reduce the false rejection rate (FRR) and/or thefalse acceptance rate (FAR) of fingerprint recognition, a reset periodP_RST may be disposed before the initialization period P_INIT to clearthe residual charge at the reset node P.

In one embodiment, in the timing chart 400, the reset period P_RST isfrom time t401 a to time t401 b before the initialization period P_INIT.At time t401 a, the voltage signal VM1 is configured to be switched froma low level to a high level to turn on the reset switch M1. After the M1is turned on, the reset node P is electrically coupled to the powersupply node to receive the voltage signal Vsig, and the voltage VP isgradually increase towards the voltage signal Vsig by charging the firstcapacitor C1 during the initialization period P_INIT. In one embodiment,the voltage signal Vsig is kept at a first voltage in the reset periodP_RST and the initial voltage may be 0V, but the disclosure is notlimited thereto. At time t401 b, the voltage signal VM1 is configured tobe switched from the high level to the low level to turn off the resetswitch M1, and the voltage VP is reset to the reset voltage (0V) beforethe initialization period P_INIT. The initialization period P_INIT (timet401 to time t402), the exposure period P_EXP (time t402 to time t404),and the readout period P_READ (time t404 to time t405) may refer to thedescription of FIG. 3 , and their description is not repeated herein.Since the voltage VP is reset to the reset voltage (0V) before theinitialization period P_INIT, the influence of the residual voltage atthe reset node P to the stability of the fingerprint images is reduced,and as a result, the fingerprint image quality becomes more stable.Therefore, the false rejection rate (FRR) and/or the false acceptancerate (FAR) of fingerprint recognition is reduced and the accuracy of thefingerprint recognition is improved.

FIG. 5 is a schematic diagram of a fingerprint sensor array according toone embodiment of the disclosure. Referring to FIG. 1 and FIG. 5 , afingerprint sensor array 500 may include a plurality of fingerprintsensors 510. The fingerprint sensors 510 may refer to the description offingerprint sensor 110 of FIG. 1 , and the description is not repeatedherein. In one embodiment, the fingerprint sensors array 500 may includen rows and n column, but the disclosure is not limited thereto. Thefingerprint sensors 510 may be arranged at the intersection of each rowand each column. The fingerprint sensors 510 may be coupled to aplurality of sensing lines SO1˜SOn, a plurality of reset lines GS1˜GSn,and a plurality of fingerprint scan lines SF1˜SFn. The sensing linesSO1˜SOn may be coupled to the fingerprint readout circuit 120. In oneembodiment, the sensing lines SO1˜SOn may be coupled to the fingerprintreadout circuit 120 through a plurality of output terminals T1˜Tn, butthe disclosure is not limited thereto. The reset lines GS1˜GSn may beconfigured to provide a voltage signal to the gate of the reset switchM1 of the fingerprint sensor 510. The fingerprint scan lines SF1˜SFn maybe configured to provide a voltage signal to the gate of the selectswitch M3 of the fingerprint sensor 510. In this manner, the fingerprintsensor array 500 may integrate the plurality of fingerprint sensors 510to realize the fingerprint recognition.

FIG. 6 is a schematic timing chart of a fingerprint sensor arrayaccording to one embodiment of the disclosure. Referring to FIG. 3 ,FIG. 5 , and FIG. 6 , in the timing chart 600, the work voltage VDD ofthe voltage signal Vsig may be represented as VDD. Row1_M1 may representa voltage signal of the gate of the reset switch M1 of the first row inthe fingerprint sensor array 500. Row2_M1 may represent a voltage signalof the gate of the reset switch M1 of the second row in the fingerprintsensor array 500. RowN_M1 may represent a voltage signal of the gate ofthe reset switch M1 of the Nth row in the fingerprint sensor array 500.Rowl_M3 may represent a voltage signal of the gate of the select switchM3 of the first row in the fingerprint sensor array 500. Row2_M3 mayrepresent a voltage signal of the gate of the select switch M3 of thesecond row in the fingerprint sensor array 500. RowN_M3 may represent avoltage signal of the gate of the select switch M3 of the Nth row in thefingerprint sensor array 500.

In this embodiment, the timing chart 600 may include a plurality offingerprint frame periods FPR. The fingerprint frame periods FPR mayinclude frame period F601, frame period F602, and frame period F603. Inthis embodiment, the reset period P_RST may be arranged in the frameperiod F601. In the reset period P_RST, the voltage signal Vsig may bekept at the first voltage. The voltage VP of the fingerprint sensor 510of each row may be reset row by row sequentially. In other words, thefingerprint sensors 510 may be reset row by row in the reset periodP_RST.

In this embodiment, the initialization period P_INIT may be arranged inthe frame period F602. In the fingerprint sensing cycle, the voltagesignal Vsig may be kept at the initial voltage. The voltage signal VM1of the gate of the reset switch M1 of each row may be switched from thelow level to the high level for the initialization of the fingerprintsensors 510. Further, the voltage signal VM1 of the gate of the resetswitch M1 of each row may be switched from the high level to the lowlevel for the exposure of the fingerprint sensors 510.

In this embodiment, the readout period P_READ may be arranged in theframe period F603. The voltage signal of the gate of the select switchM3 of each row may be switched from the low level to the high level forthe readout of the fingerprint sensors 510.

In this manner, the reset period P_RST may be arranged in one periodbefore the fingerprint sensing cycle to row by row reset the voltage VPof the reset node P of the fingerprint sensors 510, and as a result, thefingerprint image quality becomes more stable. Therefore, the falserejection rate (FRR) and/or the false acceptance rate (FAR) offingerprint recognition is reduced and the accuracy of the fingerprintrecognition is improved.

FIG. 7 is a schematic timing chart of a fingerprint sensor arrayaccording to one embodiment of the disclosure. Referring to FIG. 3 toFIG. 7 , in the timing chart 700, instead of arranging the reset periodP_RST separately in the single frame period F601, the reset period P_RSTand the initialization period P_INIT may belong to the same frame periodF701. Specifically, the reset period P_RST may be arranged at thebeginning of the frame period F701, and the initialization period P_INITmay be arranged right after the reset period in the frame period F701.In the reset period P_RST, the voltage signal Vsig may be kept at thefirst voltage. The voltage VP of the fingerprint sensor 510 of each rowmay be reset simultaneously. In other words, the fingerprint sensors 510may be reset simultaneously in the reset period P_RST. That is, all ofthe gates of the fingerprint sensors 510 may be turned on simultaneouslyin the reset period P_RST. The initialization period P_INIT, and thereadout period P_READ may refer to the description of FIG. 6 , and theirdescription is not repeated herein.

In this manner, the reset period P_RST may be arranged in one periodbefore the fingerprint sensing cycle to simultaneously reset the voltageVP of the reset node P of the fingerprint sensors 510, and as a result,the fingerprint image quality becomes more stable. Therefore, the falserejection rate (FRR) and/or the false acceptance rate (FAR) offingerprint recognition is reduced and the accuracy of the fingerprintrecognition is improved.

FIG. 8 is a schematic diagram of a touch display panel including afingerprint sensor array according to one embodiment of the disclosure.Referring to FIG. 5 and FIG. 8 , the touch display panel 800 may beformed by integrating the fingerprint sensor array 500 and a pluralityof pixels 820. That is, the touch display panel 800 may include aplurality of fingerprint sensors 810. The fingerprint sensors 810 mayrefer to the description of fingerprint sensors 510 of FIG. 5 , and thedescription is not repeated herein.

In this embodiment, each of the pixels 820 may include a pixel switchM4, a second capacitor C2, and a third capacitor C3. The pixel switch M4may include a first terminal, a second terminal, and a control terminal.The second capacitor C2 may include a first terminal and a secondterminal. The third capacitor C3 may include a first terminal and asecond terminal. The second terminal of the pixel switch M4 may beelectrically coupled to the first terminal of the second capacitor C2and the first terminal of the third capacitor C3.

The touch display panel 800 may further include a plurality of displayscan lines GD1˜GDn and a plurality of display data lines SD1˜SDn. Thedisplay scan lines GD1˜GDn may be configured to provide a gate drivingvoltage to a gate (i.e. the control terminal) of the pixel switch M4 ofeach pixel 820. The display data lines SD1˜SDn may be configured toprovide a data voltage to the first terminal of the pixel switch M4 ofeach pixel 820. In one embodiment, the display data lines SD1˜SDn may becoupled to a data driving circuit through a plurality of outputterminals TP1˜TPn, but the disclosure is not limited thereto. In thismanner, the touch display panel 800 may integrate the plurality offingerprint sensors 810 with the plurality of pixels.

It is noted that, referring to FIG. 1 , FIG. 2 and FIG. 8 , theplurality of fingerprint sensors 810 arranged in an array may be locatedin the touch display panel 800. The touch display panel 800 may includea gate on array (GOA) circuit for fingerprint sensing control. Thefingerprint readout circuit 120 may output at least one start pulsesignal STV and a clock signal CLK to the gate on array circuit forfingerprint sensing control. For example, if the fingerprint sensorarray is divided into four fingerprint sensing zones FZ1-FZ4 along thevertical direction (i.e. fingerprint scanning direction), thefingerprint readout circuit 120 may provide start pulse signalsSTV1-STV4. Further, the GOA circuit for fingerprint sensing control mayinclude four corresponding shift register circuits, wherein each shiftregister circuit may generate reset signals RST correspondingly providedto the plurality of reset lines GS1˜GSn connected to one of thefingerprint sensing zones FZ1-FZ4, based on one of the start pulsesignals STV1-STV4 and the clock signal CLK. In other words, the gate onarray circuit may outputs reset signals RST according to the at leastone start pulse signal STV and the clock signal CLK. The reset signalsRST may be configured to reset at least one fingerprint sensing zone ofthe fingerprint sensors 810 arranged in the array row by row in thereset period P_RST. For example, sensor rows of the fingerprint sensingzone FZ1 may be reset row-by-row by the reset signals RST transmitted tothe fingerprint sensing zone FZ1 which are generated based on the startpulse signal STV1 and the clock signal CLK. Sensor rows of thefingerprint sensing zone FZ2 may be reset row-by-row by the resetsignals RST transmitted to the fingerprint sensing zone FZ2 which aregenerated based on the start pulse signal STV2 and the clock signal CLK.Sensor rows of the fingerprint sensing zone FZ3 may be reset row-by-rowby the reset signals RST transmitted to the fingerprint sensing zone FZ3which are generated based on the start pulse signal STV3 and the clocksignal CLK. Sensor rows of the fingerprint sensing zone FZ4 may be resetrow-by-row by the reset signals RST transmitted to the fingerprintsensing zone FZ4 which are generated based on the start pulse signalSTV4 and the clock signal CLK. That is, the voltage VP of the reset nodeP of the fingerprint sensors 810 may be reset row by row according tothe start pulse signal STV and the clock signal CLK output from thefingerprint readout circuit 120. It is noted that, initializationsignals for row-by row initializing the sensor rows of each fingerprintsensing zones and the reset signals RST are both output to the pluralityof reset lines GS1˜GSn.

In one embodiment, the fingerprint readout circuit 120 may output atleast one start pulse signal STV, a clock signal CLK, and a controlsignal SIM to the gate on array circuit for fingerprint sensing control.For example, if the fingerprint sensor array is divided into fourfingerprint sensing zones FZ1-FZ4 along the vertical direction (i.e.fingerprint scanning direction), the fingerprint readout circuit 120 mayprovide start pulse signals STV1-STV4 and the control signal SIM.Further, the GOA circuit for fingerprint sensing control may includefour corresponding shift register circuits, wherein each shift registercircuit may generate reset signals RST correspondingly provided to theplurality of reset lines GS1˜GSn connected to one of the fingerprintsensing zones FZ1-FZ4, based on one of the start pulse signals STV1-STV4and the clock signal CLK. Furthermore, the shift register circuit may beconfigured to provide the reset signals RST to one or more of thefingerprint sensing zones FZ1-FZ4, which are able to simultaneouslyreset all sensor rows of the one or more of the fingerprint sensingzones FZ1-FZ4, and such reset signals RST are generated according to thecontrol signal SIM. In other words, the gate on array circuit forfingerprint sensing control may outputs reset signals RST according tothe at least one start pulse signal STV, the clock signal CLK, and thecontrol signal SIM. The reset signals RST may be configured tosimultaneously reset at least one fingerprint sensing zone of thefingerprint sensors 810 arranged in the array in the reset period P_RST.For example, the reset signals RST may be simultaneously configured toreset sensor rows of the fingerprint sensing zone FZ1˜FZ4 based on thestart pulse signal STV1˜STV4, the clock signal CLK and the controlsignal SIM. That is, the voltage VP of the reset node P of thefingerprint sensors 810 may be reset simultaneously according to thestart pulse signal STV, the clock signal CLK, and the control signal SIMof the fingerprint readout circuit 120.

In one embodiment, the fingerprint readout circuit 120 may output atleast one start pulse signal STV and a clock signal CLK to the gate onarray circuit for fingerprint sensing control. For example, if thefingerprint sensor array is divided into four fingerprint sensing zonesFZ1-FZ4 along the vertical direction (i.e. fingerprint scanningdirection), the fingerprint readout circuit 120 may provide start pulsesignals STV1-STV4. Further, the GOA circuit for fingerprint sensingcontrol may include four corresponding shift register circuits, whereineach shift register circuit may generate selecting signals SELcorrespondingly provided to the plurality of fingerprint scan linesSF1˜SFn connected to one of the fingerprint sensing zones FZ1-FZ4, basedon one of the start pulse signals STV1-STV4 and the clock signal CLK. Inother words, the gate on array circuit for fingerprint sensing controlmay outputs selecting signals SEL according to the at least one startpulse signal STV and the clock signal CLK. The selecting signals SEL maybe configured to row-by-row read out sensing voltages (the output offingerprint sensor 200) of at least one fingerprint sensing zone of thefingerprint sensors 810 arranged in the array in the readout periodP_READ. For example, sensing voltages of sensor rows of the fingerprintsensing zone FZ1 may be readout row-by row by the selecting signals SELtransmitted to the fingerprint sensing zone FZ1 which are generatedaccording to the start pulse signal STV1 and the clock signal CLK.Sensing voltages of sensor rows of the fingerprint sensing zone FZ2 maybe readout row-by row by the selecting signals SEL transmitted to thefingerprint sensing zone FZ2 which are generated according to the startpulse signal STV2 and the clock signal CLK. Those selecting signals SELtransmitted to the fingerprint sensing zone FZ3 or FZ4 are generated ina similar manner. That is, the sensing voltages of the sensor rows ofthe fingerprint sensors 810 may be read out row by row according to thestart pulse signal STV and the clock signal CLK of the fingerprintreadout circuit 120.

FIG. 9 is a schematic timing chart of a touch display panel including afingerprint sensor array according to first embodiment of thedisclosure. Referring to FIG. 6 to FIG. 9 , the timing chart 900 mayinclude a plurality of frame periods F901˜F907. Further, the timingchart 900 may include a plurality of fingerprint frame periods denotedby FPR, and a plurality of touch display frame periods denoted by DP+TP.Furthermore, in the timing chart 900, a mode signal Sync may representthe mode of the touch display panel 800. When the mode signal Sync is ata high level, a fingerprint sensing function of the touch display panel800 may be enabled, and a display function and a touch sensing functionof the touch display panel 800 may be disabled. When the mode signalSync is at a low level, a fingerprint sensing function of the touchdisplay panel 800 may be disabled, and a display function and a touchsensing function of the touch display panel 800 may be enabled.

In this embodiment, frame period F901, frame period F903, frame periodF905, and F907 may be the touch display frame periods DP+TP, and frameperiod F902, frame period F904, and frame period F906 may be thefingerprint frame periods FPR. In the fingerprint frame periods FPR, thereset period P_RST may belong to the frame period F902, theinitialization period P_INIT may belong to the frame period F904, andthe readout period P_READ may belong to the frame period F906. That is,one frame between two consequent touch display frame periods DP+TP maybe arranged for the fingerprint frame period FPR. In other words, thetouch display frame periods DP+TP and the fingerprint frame periods FPRmay be arranged alternatively in the timing chart 900. The operationmode of the touch display panel 800 with this kind of arrangement may benamed as “frame skip mode”.

It is noted that, one cycle of the fingerprint sensing cycle may bedefined from the initialization period P_INIT to the readout periodP_READ. The initialization period P_INIT of the fingerprint sensingcycle may be in a first frame period. The readout period P_READ of thefingerprint sensing cycle may be in a second frame period different fromthe first frame period. That is, one fingerprint sensing cycle may bedefined from the frame period F904 to the frame period F906. In thisembodiment, one touch display frame period DP+TP (frame period F905) isarranged between frame period F904 where the initialization periodP_INIT belongs to and frame period F906 where the readout period P_READbelongs to of a same fingerprint cycle. However, the number of the touchdisplay frame periods between a fingerprint sensing frame period wherethe initialization period P_INIT belongs to and another fingerprintsensing frame period where the readout period P_READ belongs to of thesame fingerprint cycle is not limited thereto. In other words, a timelength between the initialization period P_INIT and the readout periodP_READ may include one or more frame periods. In the one or more frameperiods between the initialization period P_INIT and the readout periodP_READ, at least one of a display function and a touch sensing functionis enabled and a fingerprint sensing function is disabled.

In this embodiment, the reset period P_RST may be arranged in the frameperiod F902. The voltage VP of the reset node P of each fingerprintsensors 810 of the touch display panel 800 may be reset row by row inthe reset period P_RST. In this embodiment, after the frame period F902which the reset period P_RST is in, there is one fingerprint sensingcycle arranged from the frame period F904 to the frame period F906, butthe number of fingerprint sensing cycles arranged after the reset periodP_RST is not limited thereto.

Furthermore, in this embodiment, one touch display frame period DP+TP(frame period F903) is arranged between the reset period P_RST (frameperiod F902) and the initialization period P_INIT (frame period F904).However, the number of the touch display frame periods DP+TP between afingerprint sensing frame period where the reset period P_RST belongs toand another fingerprint sensing frame period where the initializationperiod P_INIT belongs to of a same cycle is not limited thereto. Thatis, a time length between the reset period P_RST and the fingerprintsensing cycle may include one or more frame periods. In the one or moreframe periods between the reset period P_RST and the fingerprint sensingcycle, at least one of a display function and a touch sensing functionis enabled and a fingerprint sensing function is disabled. In addition,the fingerprint sensors 810 are reset row by row in the reset periodP_RST.

FIG. 10 is a schematic timing chart of a touch display panel including afingerprint sensor array according to second embodiment of thedisclosure. Referring to FIG. 8 to FIG. 10 , the timing chart 1000 mayinclude a plurality of frame periods F1001˜F1011.

In this embodiment, frame periods F1001, F1003, F1005, F1007, F1009, andF1011 may be the touch display frame periods DP+TP, and frame periodsF1002, F1004, F1006, F1008, and F1010 may be the fingerprint frameperiods FPR.

In the fingerprint frame period FPR, the reset period P_RST may belongto the frame period F1002. The initialization period P_INIT of a firstfingerprint sensing cycle Cycle1 may belong to the frame period F1004,and the readout period P_READ of the first fingerprint sensing cycleCycle1 may belong to the frame period F1006. The initialization periodP_INIT of a second fingerprint sensing cycle Cycle2 may belong to theframe period F1006, and the readout period P_READ of the secondfingerprint sensing cycle Cycle2 may belong to the frame period F1008.The initialization period P_INIT of an Nth fingerprint sensing cycleCycleN may belong to the frame period F1008, and the readout periodP_READ of the Nth fingerprint sensing cycle CycleN may belong to theframe period F1010.

That is, one reset period P_RST may be arranged before N fingerprintsensing cycles. In other words, the voltage VP of the reset node P ofeach fingerprint sensors 810 of the touch display panel 800 may be resetrow by row in the reset period P_RST before the N fingerprint sensingcycles, and as a result, the fingerprint image quality becomes morestable. Therefore, the false rejection rate (FRR) and/or the falseacceptance rate (FAR) of fingerprint recognition is reduced and theaccuracy of the fingerprint recognition is improved.

Further, the readout period P_READ of the first fingerprint sensingcycle Cycle1 and the initialization period P_INIT of the secondfingerprint sensing cycle Cycle2 may belong to the same frame periodF1006. The readout period P_READ of the second fingerprint sensing cycleCycle2 and the initialization period P_INIT of the Nth fingerprintsensing cycle CycleN may belong to the same frame period F1008. That is,the readout period P_READ of a cycle and the initialization periodP_INIT of a next fingerprint sensing cycle may belong to the same frameperiod. Therefore, the frame periods required for N fingerprint sensingcycles may be reduced.

FIG. 11 is a schematic timing chart of a touch display panel including afingerprint sensor array according to third embodiment of thedisclosure. Referring to FIG. 8 to FIG. 11 , the timing chart 1100 mayinclude a plurality of frame periods F1101˜F1113.

In this embodiment, frame periods F1101, F1103, F1105, F1107, F1109,F1111, and F1113 may be the touch display frame periods DP+TP, and frameperiods F1102, F1104, F1106, F1108, F1110, and F1112 may be thefingerprint frame periods FPR.

In the fingerprint frame periods FPR, the reset period P_RST of a firstfingerprint sensing cycle Cycle1 may belong to the frame period F1102,and the reset period P_RST of a Nth fingerprint sensing cycle CycleN maybelong to the frame period F1108. The initialization period P_INIT ofthe first fingerprint sensing cycle Cycle1 may belong to the frameperiod F1104, and the readout period P_READ of the first fingerprintsensing cycle Cycle1 may belong to the frame period F1106. Theinitialization period P_INIT of an Nth fingerprint sensing cycle CycleNmay belong to the frame period F1110, and the readout period P_READ ofthe Nth fingerprint sensing cycle CycleN may belong to the frame periodF1112.

That is, one reset period P_RST may be arranged before each fingerprintsensing cycle. In other words, the voltage VP of the reset node P ofeach fingerprint sensors 810 of the touch display panel 800 may be resetrow by row in the reset period P_RST before each fingerprint sensingcycle, and as a result, the fingerprint image quality becomes morestable. Therefore, the false rejection rate (FRR) and/or the falseacceptance rate (FAR) of fingerprint recognition is reduced and theaccuracy of the fingerprint recognition is improved.

FIG. 12 is a schematic timing chart of a touch display panel including afingerprint sensor array according to fourth embodiment of thedisclosure. Referring to FIG. 8 to FIG. 12 , the timing chart 1200 mayinclude a plurality of frame periods F1201˜F1208.

In this embodiment, frame periods F1201, F1203, F1205, F1206, and F1207may be the touch display frame periods DP+TP, and frame periods F1202,F1204, and F1208 may be the fingerprint frame periods FPR. In thefingerprint frame periods FPR, the reset period P_RST may belong to theframe period F1202, the initialization period P_INIT may belong to theframe period F1204, and the readout period P_READ may belong to theframe period F1208.

In this embodiment, touch display frame periods DP+TP (frame periodsF1205˜F1207) may be arranged between two consequent fingerprint frameperiods FPR (frame periods F1204 and F1208) of a same fingerprintsensing cycle. That is, between the initialization period P_INIT and thereadout period P_READ of the same fingerprint sensing cycle, a pluralityof touch display frame periods DP+TP may be arranged. In other words, atime length between the initialization period P_INIT and the readoutperiod P_READ may include one or more frame periods. In the one or moreframe periods between the initialization period P_INIT and the readoutperiod P_READ, at least one of a display function and a touch sensingfunction is enabled and a fingerprint sensing function is disabled.

FIG. 13 is a schematic timing chart of a touch display panel including afingerprint sensor array according to fifth embodiment of thedisclosure. Referring to FIG. 8 to FIG. 13 , the timing chart 1300 mayinclude a plurality of frame periods F1301˜F1305.

In this embodiment, frame periods F1301, F1303, and F1305 may be thetouch display frame periods DP+TP, and frame periods F1302, and F1304may be the fingerprint frame periods FPR. In the fingerprint frameperiods FPR, the reset period P_RST and the initialization period P_INITof the fingerprint sensing cycle may belong to the same frame periodsF1302. Further, instead of resetting the fingerprint sensors 810 row byrow, the fingerprint sensors 810 may be reset simultaneously. Therefore,the time for resetting all the fingerprint sensors 810 of the touchdisplay panel 800 may be reduced.

In this embodiment, one touch display frame period DP+TP (frame periodF1303) is arranged between the reset period P_RST (frame period F1302)and the initialization period P_INIT (frame period F1304) of a samefingerprint sensing cycle. However, the number of the touch displayframe periods DP+TP between the reset period P_RST and theinitialization period P_INIT of the same fingerprint sensing cycle isnot limited thereto.

FIG. 14 is a schematic timing chart of a touch display panel including afingerprint sensor array according to sixth embodiment of thedisclosure. Referring to FIG. 8 to FIG. 14 , the timing chart 1400 mayinclude a plurality of frame periods F1401˜F1407.

In this embodiment, frame periods F1401, F1403, F1404, F1405, and F1407may be the touch display frame periods DP+TP, and frame periods F1402,and F1406 may be the fingerprint frame periods FPR. In the fingerprintframe periods FPR, the reset period P_RST and the initialization periodP_INIT of the fingerprint sensing cycle may belong to the same frameperiod F1402. Further, instead of resetting the fingerprint sensors 810row by row, the fingerprint sensors 810 may be reset simultaneously.Therefore, the time for resetting all the fingerprint sensors 810 of thetouch display panel 800 may be reduced.

In this embodiment, touch display frame periods DP+TP (frame periodsF1403˜1405) may be arranged between two consequent fingerprint frameperiods FPR (frame periods F1402 and F1406) of a same fingerprintsensing cycle. That is, between the initialization period P_INIT and thereadout period P_READ of the same fingerprint sensing cycle, a pluralityof touch display frame periods DP+TP may be arranged. In other words, atime length between the initialization period P_INIT and the readoutperiod P_READ may include one or more frame periods. In the one or moreframe periods between the initialization period P_INIT and the readoutperiod P_READ, at least one of a display function and a touch sensingfunction is enabled and a fingerprint sensing function is disabled.

Different from the aforementioned frame skip mode, “porch mode” is alsoan operation mode for fingerprint sensing of the touch display panel800. In the porch mode, fingerprint sensing operations such asinitialization, readout and resetting before the fingerprint sensingcycle are performed in porch intervals. It is noted that, a porchinterval may be defined as a time length between the end of outputting adisplay frame of the touch display panel 800 and the beginning ofoutputting a next display frame of the touch display panel 800. That is,the entire porch interval may be between two adjacent frames. A part ofthe porch interval is located in a current frame period and the otherpart of the porch interval is located in a next frame period. The lengthof a porch interval may be predetermined based on a display refresh rateof the touch display panel 800. When the display refresh rate isvariable, which is called variable refresh rate (VRR), the length of theporch interval may be also variable.

In one embodiment, the reset period P_RST and the fingerprint sensingcycle may be performed in a porch interval. The porch interval may belocated in two adjacent frame periods. That is to say, the reset periodP_RST and the fingerprint sensing cycle may be arranged in the porchinterval between two consequent touch display frame period DP+TP.

In the porch interval, the plurality of fingerprint sensors 810 mayreset row by row in the reset period P_RST. In another embodiment, allof rows of the plurality of fingerprint sensors 810 may be resetsimultaneously in the reset period P_RST, and the disclosure is notlimited thereto.

In one embodiment, the reset period P_RST may be in a first porchinterval. The fingerprint sensing cycle may be completely performed by aplurality of second porch intervals coming after the first porchinterval. Further, any of the first porch interval and the second porchintervals may be located in two adjacent frame periods. That is to say,the reset period P_RST and the fingerprint sensing cycle may be arrangedin different porch intervals. The initialization period P_INIT, theexposure period P_EXP, and the readout period P_READ of the samefingerprint sensing cycle may be arranged in different porch intervals.

FIG. 15 is a schematic diagram of a fingerprint readout circuitaccording to one embodiment of the disclosure. Referring to FIG. 2 ,FIG. 8 and FIG. 15 , a fingerprint readout circuit 1500 is configurableto be coupled to a touch display panel 1510. The touch display panel mayinclude a plurality of fingerprint sensors 1521 arranged in a sensorarray 1520 and a gate on array circuit 1530 for fingerprint sensingcontrol. The fingerprint readout circuit 1500 may be coupled to theplurality of fingerprint sensors 1521 via a plurality of sensing lines1540. The fingerprint readout circuit 1500 may be coupled to the gate onarray circuit 1530. The fingerprint readout circuit 1500 may beconfigured to output at least one start pulse signal STV and at leastone clock signal CLK to control the gate on array circuit 1530 to outputreset signals RST and selecting signals SEL. The reset signals RST andthe selecting signals SEL may be configured to control at least onefingerprint sensing zone of the fingerprint sensors 1521 arranged in thesensor array 1520 to operate in a fingerprint sensing cycle. Thefingerprint sensing cycle may include an initialization period P_INIT,an exposure period P_EXP, and a readout period P_READ. According to thereset signals RST, a voltage VP of a reset node P in each fingerprintsensor 1521 among the fingerprint sensors 1521 may be reset to a firstvoltage in a reset period P_RST before the fingerprint sensing cyclestarts. The voltage VP of the reset node P in each fingerprint sensor1521 may be initialized to an initial voltage in the initializationperiod P_INIT. The initial voltage is different from the first voltage.

In one embodiment, the fingerprint readout circuit 1500 may beconfigured to output a voltage signal Vsig to the touch display panel1510. The voltage signal Vsig may be kept at the first voltage in thereset period P_RST. The voltage signal Vsig may be kept at the initialvoltage in the initialization period P_INIT. The first voltage isdifferent from the initial voltage. For example, the first voltage is 0Vand the initial voltage is a work voltage such as 4V.

In one embodiment, the reset node P may be electrically coupled to apower supply node supplied with the voltage signal Vsig.

In one embodiment, the fingerprint readout circuit 1500 may output atleast one start pulse signal STV and a clock signal CLK to the gate onarray circuit 1530. The gate on array circuit 1530 may output resetsignals RST according to the at least one start pulse signal STV and theclock signal CLK. The reset signals RST may be configured to reset atleast one fingerprint sensing zone of the fingerprint sensors 1521arranged in the sensor array 1520 row by row in the reset period P_RST.

In one embodiment, the fingerprint readout circuit 1500 may output atleast one start pulse signal STV, a clock signal CLK and a controlsignal SIM to the gate on array circuit 1530. For example, if thefingerprint sensor array is divided into four fingerprint sensing zonesFZ1-FZ4 along the vertical direction (i.e. fingerprint scanningdirection), the fingerprint readout circuit 120 may provide start pulsesignals STV1-STV4 and the control signal SIM. Further, the gate on arraycircuit 1530 may include four corresponding shift register circuits,wherein each shift register circuit may generate reset signals RSTcorrespondingly provided to the plurality of reset lines GS1˜GSnconnected to the fingerprint sensing zones FZ1-FZ4, based on one of thestart pulse signals STV1-STV4 and the clock signal CLK. Furthermore, theshift register circuit may be configured to provide the reset signalsRST to the fingerprint sensing zones FZ1-FZ4 simultaneously according tothe control signal SIM. In other words, the gate on array circuit 1530may output reset signals RST according to the at least one start pulsesignal STV, the clock signal CLK and the control signal SIM. The resetsignals RST may be configured to simultaneously reset at least onefingerprint sensing zone of the fingerprint sensors 1521 arranged in thesensor array 1520 in the reset period P_RST.

In one embodiment, the fingerprint readout circuit 1500 may output atleast one start pulse signal STV and a clock signal CLK to the gate onarray circuit 1530. The gate on array circuit 1530 may output selectingsignals SEL according to the at least one start pulse signal STV and theclock signal CLK. The selecting signals SEL may be configured torow-by-row read out sensing voltages of at least one fingerprint sensingzone of the fingerprint sensors 1521 arranged in the sensor array 1520in the readout period P_READ.

In this manner, the reset period P_RST may be arranged before thefingerprint sensing cycle to reset the voltage VP of the reset node P ofthe fingerprint sensors 1521, and as a result, the fingerprint imagequality becomes more stable. Therefore, the false rejection rate (FRR)and/or the false acceptance rate (FAR) of fingerprint recognition isreduced and the accuracy of the fingerprint recognition is improved.

FIG. 16 is a schematic diagram of a touch display panel according to oneembodiment of the disclosure. Referring to FIG. 2 , FIG. 8 and FIG. 16 ,a touch display panel 1600 may include a plurality of sensing lines1620, a plurality of fingerprint sensors 1610. The plurality offingerprint sensors 1610 may be configured to operate in a fingerprintsensing cycle. The plurality of fingerprint sensors 1610 may be coupledto a fingerprint readout circuit 1630 via the sensing lines 1620. Thefingerprint sensing cycle includes an initialization period P_INIT, anexposure period P_EXP and a readout period P_READ. A voltage VP of areset node P in each fingerprint sensor 1610 among the fingerprintsensors 1610 may be reset to a first voltage in a reset period P_RSTbefore the fingerprint sensing cycle starts. The voltage VP of the resetnode P in each fingerprint sensor 1610 may be initialized to an initialvoltage in the initialization period P_INIT. The initial voltage isdifferent from the first voltage.

In one embodiment, a sensing voltage (the output of fingerprint sensor200) of each fingerprint sensors 1610 may be readout by the fingerprintreadout circuit 1630 via the corresponding sensing line 1620. Thesensing voltage of each fingerprint sensor 1610 follows the voltage VPof the reset node P. A sensing result of each fingerprint sensors 1610may be generated by the fingerprint readout circuit 1630 for thefingerprint sensing cycle based on a voltage variation between theinitial voltage and the sensing voltage.

In one embodiment, referring to FIG. 15 and FIG. 16 , the touch displaypanel 1600 may further comprise a gate on array circuit 1530 forfingerprint sensing control. The gate on array circuit 1530 may receiveat least one start pulse signal STV and a clock signal CLK from thefingerprint readout circuit 1630. The gate on array circuit 1530 mayoutput reset signals RST according to the at least one start pulsesignal STV and the clock signal CLK. The reset signals RST may beconfigured to reset at least one fingerprint sensing zone of thefingerprint sensors 1610 arranged in the sensor array 1520 row by row inthe reset period P_RST.

In one embodiment, referring to FIG. 15 and FIG. 16 , the touch displaypanel 1600 may further comprise a gate on array circuit 1530 forfingerprint sensing control. The gate on array circuit 1530 may receiveat least one start pulse signal STV, a clock signal CLK and a controlsignal SIM from the fingerprint readout circuit 1630. The gate on arraycircuit 1530 may output reset signals RST according to the at least onestart pulse signal STV, the clock signal CLK and the control signal SIM.The reset signals RST are configured to simultaneously reset at leastone fingerprint sensing zone of the fingerprint sensors 1610 arranged inthe sensor array 1520 in the reset period P_RST.

In one embodiment, referring to FIG. 15 and FIG. 16 , the touch displaypanel 1600 may further comprise a gate on array circuit 1530 forfingerprint sensing control. The gate on array circuit 1530 may receiveat least one start pulse signal STV and a clock signal CLK from thefingerprint readout circuit 1630. The gate on array circuit 1530 mayoutputs selecting signals SEL according to the at least one start pulsesignal STV and the clock signal CLK. The selecting signals SEL may beconfigured to row-by-row read out sensing voltages of at least onefingerprint sensing zone of the fingerprint sensors 1610 arranged in thesensor array 1520 in the readout period P_READ.

In this manner, the reset period P_RST may be arranged before thefingerprint sensing cycle to reset the voltage VP of the reset node P ofthe fingerprint sensors 1610, and as a result, the fingerprint imagequality becomes more stable. Therefore, the false rejection rate (FRR)and/or the false acceptance rate (FAR) of fingerprint recognition isreduced and the accuracy of the fingerprint recognition is improved.

In summary, according to the fingerprint sensing apparatus, thefingerprint readout circuit, and the touch display panel of thedisclosure, the reset period is arranged before the fingerprint sensingcycle to reset the voltage of the reset node of the fingerprint sensors.Consequently, the fingerprint image quality becomes more stable, and thefalse rejection rate (FRR) and/or the false acceptance rate (FAR) offingerprint recognition is reduced and the accuracy of the fingerprintrecognition is improved.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the disclosed embodimentswithout departing from the scope or spirit of the disclosure. In view ofthe foregoing, it is intended that the disclosure covers modificationsand variations provided that they fall within the scope of the followingclaims and their equivalents.

What is claimed is:
 1. A fingerprint sensing apparatus, comprising: aplurality of fingerprint sensors, configured to operate in a fingerprintsensing cycle; and a fingerprint readout circuit, coupled to theplurality of fingerprint sensors via a plurality of sensing lines, andconfigured to control the plurality of fingerprint sensors to operate inthe fingerprint sensing cycle, wherein the fingerprint sensing cycleincludes an initialization period, an exposure period after theinitialization period and a readout period after the exposure period, areset node is electrically coupled to a power supply node supplied witha voltage signal, wherein the voltage signal is kept at a first voltagein a reset period which is disposed before the fingerprint sensing cyclestarts and the voltage signal is kept at an initial voltage in thefingerprint sensing cycle, wherein the first voltage is smaller than theinitial voltage, and a voltage of the reset node in each fingerprintsensor among the plurality of fingerprint sensors is reset to the firstvoltage in the reset period before the fingerprint sensing cycle startsand is initialized to the initial voltage in the initialization period.2. The fingerprint sensing apparatus of claim 1, wherein the fingerprintreadout circuit reads out a sensing voltage of each fingerprint sensorvia the corresponding sensing line in the readout period, wherein thesensing voltage follows the voltage of the reset node, and thefingerprint readout circuit generates a sensing result of eachfingerprint sensor based on a voltage variation between the initialvoltage and the sensing voltage.
 3. The fingerprint sensing apparatus ofclaim 1, wherein the fingerprint readout circuit is configured to outputthe voltage signal to a touch display panel.
 4. The fingerprint sensingapparatus of claim 1, wherein the initialization period of thefingerprint sensing cycle is in a first frame period, the readout periodof the fingerprint sensing cycle is in a second frame period differentfrom the first frame period, and a time length between theinitialization period and the readout period comprises one or more frameperiods, wherein in the one or more frame periods between theinitialization period and the readout period, at least one of a displayfunction and a touch sensing function is enabled and a fingerprintsensing function is disabled.
 5. The fingerprint sensing apparatus ofclaim 1, wherein a time length between the reset period and thefingerprint sensing cycle comprises one or more frame periods, whereinin the one or more frame periods between the reset period and thefingerprint sensing cycle, at least one of a display function and atouch sensing function is enabled and a fingerprint sensing function isdisabled, and the plurality of fingerprint sensors are reset row by rowin the reset period.
 6. The fingerprint sensing apparatus of claim 1,wherein the reset period and the initialization period of thefingerprint sensing cycle belong to a same frame period, and theplurality of fingerprint sensors are reset simultaneously.
 7. Thefingerprint sensing apparatus of claim 1, wherein the reset period andthe fingerprint sensing cycle are performed in a porch interval, and theporch interval is located in two adjacent frame periods.
 8. Thefingerprint sensing apparatus of claim 7, wherein the plurality offingerprint sensors are reset row by row in the reset period.
 9. Thefingerprint sensing apparatus of claim 7, wherein the plurality offingerprint sensors are reset simultaneously.
 10. The fingerprintsensing apparatus of claim 1, wherein the reset period is in a firstporch interval, and the fingerprint sensing cycle is completelyperformed by a plurality of second porch intervals coming after thefirst porch interval, wherein any of the first porch interval and theplurality of second porch intervals is located in two adjacent frameperiods.
 11. The fingerprint sensing apparatus of claim 1, wherein theplurality of fingerprint sensors arranged in an array are located in atouch display panel, and the touch display panel comprises a gate onarray circuit, wherein the fingerprint readout circuit outputs at leastone start pulse signal and a clock signal to the gate on array circuit,and the gate on array circuit outputs reset signals according to the atleast one start pulse signal and the clock signal, wherein the resetsignals are configured to reset at least one fingerprint sensing zone ofthe plurality of fingerprint sensors arranged in the array row by row inthe reset period.
 12. The fingerprint sensing apparatus of claim 1,wherein the plurality of fingerprint sensors arranged in the array arelocated in a touch display panel, and the touch display panel comprisesa gate on array circuit, wherein the fingerprint readout circuit outputsat least one start pulse signal, a clock signal and a control signal tothe gate on array circuit, and the gate on array circuit outputs resetsignals according to the at least one start pulse signal, the clocksignal and the control signal, wherein the reset signals are configuredto simultaneously reset at least one fingerprint sensing zone of theplurality of fingerprint sensors arranged in the array in the resetperiod.
 13. The fingerprint sensing apparatus of claim 1, wherein theplurality of fingerprint sensors arranged in the array are located in atouch display panel, and the touch display panel comprises a gate onarray circuit, wherein the fingerprint readout circuit outputs at leastone start pulse signal and a clock signal to the gate on array circuit,and the gate on array circuit outputs selecting signals according to theat least one start pulse signal and the clock signal, wherein theselecting signals are configured to row-by-row read out sensing voltagesof at least one fingerprint sensing zone of the plurality of fingerprintsensors arranged in the array in the readout period.
 14. A fingerprintreadout circuit, configurable to be coupled to a touch display panel,wherein the touch display panel comprises a plurality of fingerprintsensors arranged in an array and a gate on array circuit, and thefingerprint readout circuit is coupled to the plurality of fingerprintsensors via a plurality of sensing lines, and coupled to the gate onarray circuit; and the fingerprint readout circuit is configured tooutput at least one start pulse signal and at least one clock signal tocontrol the gate on array circuit to output reset signals and selectingsignals, wherein the reset signals and the selecting signals areconfigured to control at least one fingerprint sensing zone of theplurality of fingerprint sensors arranged in the array to operate in afingerprint sensing cycle, wherein the fingerprint sensing cycleincludes an initialization period, an exposure period after theinitialization period and a readout period after the exposure period, areset node is electrically coupled to a power supply node supplied witha voltage signal, wherein the voltage signal is kept at a first voltagein a reset period which is disposed before the fingerprint sensing cyclestarts and the voltage signal is kept at an initial voltage in thefingerprint sensing cycle, wherein the first voltage is smaller than theinitial voltage, and according to the reset signals, a voltage of thereset node in each fingerprint sensor among the plurality of fingerprintsensors is reset to the first voltage in the reset period before thefingerprint sensing cycle starts and is initialized to the initialvoltage in the initialization period, wherein the reset period isdisposed before the initialization period.
 15. The fingerprint readoutcircuit of claim 14, wherein the fingerprint readout circuit reads out asensing voltage of each fingerprint sensor via the corresponding sensingline in the readout period, wherein the sensing voltage follows thevoltage of the reset node, and the fingerprint readout circuit generatesa sensing result of each fingerprint sensor based on a voltage variationbetween the initial voltage and the sensing voltage.
 16. The fingerprintreadout circuit of claim 14, wherein the fingerprint readout circuit isconfigured to output a voltage signal to the touch display panel,wherein the voltage signal is kept at the first voltage in the resetperiod, and the voltage signal is kept at the initial voltage in theinitialization period.
 17. The fingerprint readout circuit of claim 14,wherein the initialization period of the fingerprint sensing cycle is ina first frame period, the readout period of the fingerprint sensingcycle is in a second frame period different from the first frame period,and a time length between the initialization period and the readoutperiod comprises one or more frame periods, wherein in the one or moreframe periods between the initialization period and the readout period,at least one of a display function and a touch sensing function isenabled and a fingerprint sensing function is disabled.
 18. Thefingerprint readout circuit of claim 14, wherein a time length betweenthe reset period and the fingerprint sensing cycle comprises one or moreframe periods, wherein in the one or more frame periods between thereset period and the fingerprint sensing cycle, at least one of adisplay function and a touch sensing function is enabled and afingerprint sensing function is disabled, and the plurality offingerprint sensors are reset row by row in the reset period.
 19. Thefingerprint readout circuit of claim 14, wherein the reset period andthe initialization period of the fingerprint sensing cycle belong to thesame frame period, and the plurality of fingerprint sensors are resetsimultaneously.
 20. The fingerprint readout circuit of claim 14, whereinthe reset period and the fingerprint sensing cycle are performed in aporch interval, and the porch interval is located in two adjacent frameperiods.
 21. The fingerprint readout circuit of claim 20, wherein theplurality of fingerprint sensors are reset row by row in the resetperiod.
 22. The fingerprint readout circuit of claim 20, wherein theplurality of fingerprint sensors are reset simultaneously.
 23. Thefingerprint readout circuit of claim 14, wherein the reset period is ina first porch interval, and the fingerprint sensing cycle is completelyperformed by a plurality of second porch intervals coming after thefirst porch interval, wherein any of the first porch interval and theplurality of second porch intervals is located in two adjacent frameperiods.
 24. The fingerprint readout circuit of claim 14, wherein thefingerprint readout circuit outputs at least one start pulse signal anda clock signal to the gate on array circuit, and the gate on arraycircuit outputs reset signals according to the at least one start pulsesignal and the clock signal, wherein the reset signals are configured toreset at least one fingerprint sensing zone of the plurality offingerprint sensors arranged in the array row by row in the resetperiod.
 25. The fingerprint readout circuit of claim 14, wherein thefingerprint readout circuit outputs at least one start pulse signal, aclock signal and a control signal to the gate on array circuit, and thegate on array circuit outputs reset signals according to the at leastone start pulse signal, the clock signal and the control signal, whereinthe reset signals are configured to simultaneously reset at least onefingerprint sensing zone of the plurality of fingerprint sensorsarranged in the array in the reset period.
 26. The fingerprint readoutcircuit of claim 14, wherein the fingerprint readout circuit outputs atleast one start pulse signal and a clock signal to the gate on arraycircuit, and the gate on array circuit outputs selecting signalsaccording to the at least one start pulse signal and the clock signal,wherein the selecting signals are configured to row-by-row read outsensing voltages of at least one fingerprint sensing zone of theplurality of fingerprint sensors arranged in the array in the readoutperiod.
 27. A touch display panel, comprising: a plurality of sensinglines; and a plurality of fingerprint sensors, configured to operate ina fingerprint sensing cycle, and coupled to a fingerprint readoutcircuit via the plurality of sensing lines, wherein the fingerprintsensing cycle includes an initialization period, an exposure periodafter the initialization period and a readout period after the exposureperiod, a reset node is electrically coupled to a power supply nodesupplied with a voltage signal, wherein the voltage signal is kept at afirst voltage in a reset period which is disposed before the fingerprintsensing cycle starts and the voltage signal is kept at an initialvoltage in the fingerprint sensing cycle, wherein the first voltage issmaller than the initial voltage, and a voltage of the reset node ineach fingerprint sensor among the plurality of fingerprint sensors isreset to the first voltage in the reset period before the fingerprintsensing cycle starts and is initialized to the initial voltage in theinitialization period.
 28. The touch display panel of claim 27, whereina sensing voltage of each fingerprint sensors is readout by thefingerprint readout circuit via the corresponding sensing line, whereinthe sensing voltage of each fingerprint sensor follows the voltage ofthe reset node, and a sensing result of each fingerprint sensors isgenerated by the fingerprint readout circuit for the fingerprint sensingcycle based on a voltage variation between the initial voltage and thesensing voltage.
 29. The touch display panel of claim 27, wherein thefingerprint readout circuit is configured to output the voltage signalto the touch display panel.
 30. The touch display panel of claim 27,wherein the initialization period of the fingerprint sensing cycle is ina first frame period, the readout period of the fingerprint sensingcycle is in a second frame period different from the first frame period,and a time length between the initialization period and the readoutperiod comprises one or more frame periods, wherein in the one or moreframe periods between the initialization period and the readout period,at least one of a display function and a touch sensing function isenabled and a fingerprint sensing function is disabled.
 31. The touchdisplay panel of claim 27, wherein a time length between the resetperiod and the fingerprint sensing cycle comprises one or more frameperiods, wherein in the one or more frame periods between the resetperiod and the fingerprint sensing cycle, at least one of a displayfunction and a touch sensing function is enabled and a fingerprintsensing function is disabled, and the plurality of fingerprint sensorsare reset row by row in the reset period.
 32. The touch display panel ofclaim 27, wherein the reset period and the initialization period of thefingerprint sensing cycle belong to the same frame period, and theplurality of fingerprint sensors are reset simultaneously.
 33. The touchdisplay panel of claim 27, wherein the reset period and the fingerprintsensing cycle are performed in a porch interval, and the porch intervalis located in two adjacent frame periods.
 34. The touch display panel ofclaim 33, wherein the plurality of fingerprint sensors are reset row byrow in the reset period.
 35. The touch display panel of claim 33,wherein the plurality of fingerprint sensors are reset simultaneously.36. The touch display panel of claim 27, wherein the reset period is ina first porch interval, and the fingerprint sensing cycle is completelyperformed by a plurality of second porch intervals coming after thefirst porch interval, wherein any of the first porch interval and theplurality of second porch intervals is located in two adjacent frameperiods.
 37. The touch display panel of claim 27, further comprising agate on array circuit, wherein the gate on array circuit receives atleast one start pulse signal and a clock signal from the fingerprintreadout circuit, and the gate on array circuit outputs reset signalsaccording to the at least one start pulse signal and the clock signal,wherein the reset signals are configured to reset at least onefingerprint sensing zone of the plurality of fingerprint sensorsarranged in an array row by row in the reset period.
 38. The touchdisplay panel of claim 27, further comprising a gate on array circuit,wherein the gate on array circuit receives at least one start pulsesignal, a clock signal and a control signal from the fingerprint readoutcircuit, and the gate on array circuit outputs reset signals accordingto the at least one start pulse signal, the clock signal and the controlsignal, wherein the reset signals are configured to simultaneously resetat least one fingerprint sensing zone of the plurality of fingerprintsensors arranged in an array in the reset period.
 39. The touch displaypanel of claim 27, further comprising a gate on array circuit, whereinthe gate on array circuit receives at least one start pulse signal and aclock signal from the fingerprint readout circuit, and the gate on arraycircuit outputs selecting signals according to the at least one startpulse signal and the clock signal, wherein the selecting signals areconfigured to row-by-row read out sensing voltages of at least onefingerprint sensing zone of the plurality of fingerprint sensorsarranged in an array in the readout period.